Make a very simple mechanical time delay?

[supak111]

Hey everyone, I need to make or design a simple mechanical time delay. This probably isn't easy since I can't find anything on the market that's small and cheap. Was thinking some wind up toy might work, haven't found the right one yet.

I was thinking maybe small box with a rod coming out of it (but open to ideas). If you push the rod all the way in it should take time for it to come out, maybe 2-5 minutes.

HOPING TO ACHEAVE:
~ Cheap under $3 but hopefully cheaper.
~ Small (hopefully smaller than a pack of cigarettes)
~ Needs to go in fast so no mechanical gearing on the way in.
~ Comes back out very slow 2-5 mins.
~ Needs to be able to push 1lb (maybe less not sure at the moment)

Does anyone have any ideas?

PS even a battery powered one would be ok if cheap. Haven't found anything similar already manufactured still.

.

 

[berkeman]

Hey everyone, I need to make or design a simple mechanical time delay. This probably isn't easy since I can't find anything on the market that's small and cheap. Was thinking some wind up toy might work, haven't found the right one yet.

I was thinking maybe small box with a rod coming out of it (but open to ideas). If you push the rod all the way in it should take time for it to come out, maybe 2-5 minutes.

HOPING TO ACHEAVE:
~ Cheap under $3 but hopefully cheaper.
~ Small (hopefully smaller than a pack of cigarettes)
~ Needs to go in fast so no mechanical gearing on the way in.
~ Comes back out very slow 2-5 mins.
~ Needs to be able to push 1lb (maybe less not sure at the moment)

Does anyone have any ideas?

PS even a battery powered one would be ok if cheap. Haven't found anything similar already manufactured still.

.

Can you sam more about the application? Is the 1lb load on low-friction rollers, or do you need 1lb-f applied through the whole movement of the arm? How far do you need to push the load?

You could start with a basic egg timer and adapt it maybe...

https://vignette4.wikia.nocookie.ne...g_timer.png/revision/latest?cb=20110402182025

 

[Asymptotic]

A dashpot?

 

[berkeman]

A dashpot?

Interesting idea. Like with a weight to drive it?

 

[Asymptotic]

Interesting idea. Like with a weight to drive it?

Not necessarily, but not a bad thought, either. Dashpots come in a wide variety of types and ratings, for example, an air dashpot like those used in automotive carburetors may not provide 1 lb of force, but one based on hydraulics ought to. Outside of carbs, the only hands-on experience I have with them are old-fashioned pneumatic timer relays like the Allen-Bradley bulletin 700-NT, but (although the under $3 criteria may not be obtainable) I bet Google would turn up something to fit the bill.

 

[supak111]

Thanks for your replies guys.

Dashpot sounds like a perfect idea especially since I won't have to modify it much. What makes the dashpot cool is most have adjustable timing like the dashpots on your house screen doors. Clock timer is a good one too if I can modify it to fit.

And the 1lb of push force might be over kill, I was just roughly estimating here. I'm going to do some searching and see if I can find a dashpot that's pretty cheap and small hopefully adjustable timing too.

 

[Tom.G]

searching and see if I can find a dashpot that's pretty cheap and small

Not adjustable, but a hypodermic syringe meets the other qualifications. It does have a bit of static friction though.